Burner air directing means



July 3, 1962 G. MBITTERLICH 3,042,105

BURNER AIR DIRECTING MEANS Filed Jan. 29,` 1959 2 6 l gMmm-l mvEN'u'oR: GORDON M. BITTERLICH United States Patent O 3,042,105 BURNER AER DREC'HNG MEANS Gordon M. Bitteriich, Wayne, Pa., assigner to Thermal Research & Engineering Corporation, Conshohocken, Pa., a corporation of Delaware Filed Jan. 29, 1959, Ser. No. 790,004, 3 Claims. (Ci. 158-15) The present invention relates to new and useful improvements in burners and more particularly to new and useful improvements in burners for burning fluid fuels with a high effectiveness including not only light fuels but also heavy fuels such as viscous residual oils, tars and asphalt.

A principal object of the present invention is to provide a novel burner construction which may be used as a combination gaseous and liquid burner and which will completely burn heavy fuels such as viscous residual oils, tars and asphalt at a rapid rate of combustion in a relatively small combustion chamber without building up carbon deposits on the walls of the combustion chamber.

Another object of the present invention is to provide a novel burner of the above mentioned type having novel air distributing means operable to distribute the combustion air uniformly -across the entrance to the combustion chamber and impart a swirling motion to the air entering the combustion chamber to cause the air to follow a predetermined path in the combustion chamber.

A further and extremely important object of the present invention is to provide a novel burner in which a rapid swirling movement is imparted to the air entering the combustion chamber with a minimum pressure drop across the air distributing means.

A still further object of the present invention is to provide a novel burner having the features and characteristics set forth above which is of relatively simplified construction, maybe manufactured easily and cheaply, and is entirely eihcient and effective in operation and use.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth and described with reference to the accompanying drawings, in which:

FIG. l is a longitudinal sectional view through a burner made in accordance with the present invention; and

FIG. 2 is a transverse sectional view taken on line 2-2, FIG. 1 illustrating the air distributing means.

Referring more particularly to the drawings, there is illustrated therein a burner made in accordance with the present invention comprising a substantially cylindrical combustion chamber the walls 11 of which are formed of any suitable refractory material. An inlet opening 12 of lesser diameter than the combustion chamber is provided substantially centrally of the rear wall thereof through which the fuel and air pass upon entering the combustion chamber.

in accordance with the present invention, the fuel and air entering the combustion chamber is caused to swirl in the form of a continuously advancing and diverging annulus so that the lfuel and air are caused to mix thoroughly and remain in the relatively small combustion chamber for a relatively @long period of time. Additionally, because of the central opening in the rear wall of the combustion chamber and the swirling movement of the fuel and air, flame vortices are formed adjacent the combustion chamber central opening and adjacent the longitudinal centerline of the burner forwardly of the central opening further -mixing the fuel and air and bringing the atomized fuel up to the ignition temperature thereby insurinU complete and rapid combustion. This desired swirling movement and the resultant flame vortices is accomplished with a minimum pressure drop by 3,042,105 Patented July 3, 1962 carefully controlling the path of travel of the air prior to the air entering the combustion chamber.

Accordingly, the present invention provides an air inlet chamber 13 formed by an enclosed housing 14 which may be of generally cylindrical form positioned rearwardly of the combustion chamber 10 substantially coaxially with the opening 12 'to the combustion chamber. The cornbustion air is admitted to the air chamber 13 -through an air inlet 15 positioned on the peripheral edge of the housing 14 and extending substantially radially to the housing 14. The swirling movement is imparted to the combustion air by means of a series of vanes 16 which may be in the `form of a series of flat plates spaced equally about the 'longitudinal center line of the combustion chamber. The vanes 16 diverge outwardly in a direction away from the rear wall of the housing 14 toward the central inlet opening 12 to the combustion chamber, and are each disposed at an angle relative to a tangent to an imaginary circle drawn about the longitudinal center line of the combustion chamber. Openings 16a are provided between adjacent vanes 16 through which the combustion air passes with the openings becoming wider in a direction toward the rear wall of fthe combustion chamber. These openings between divergent vanes cause the combustion air to be distributed uniformly in the annular cone shaped area formed by the vanes. This is accomplished by carefully matching the increasing area of the vane openings in a direction toward the combustion chamber with the increasing volume of the cone yformed by the vanes. With this construction, the swirling combustion `air exiting from the vanes is laid down in overlapping 'layers insuring a substantially uniform forward velocity of the air which will be much lower in magnitude than the tangential velocity of the air and minimizing undesired turbulence and pressure drop in this cone area.

Positioned intermediate the peripheral wall of the housing 14 and the series of vanes 16 is an air distribution shroud or baille 17 which surrounds the vanes 16 and preferably is coaxial with the series of vanes. This air ydistribution shroud 17 is designed to distribute the combustion `air in the air chamber 13 equally about the periphery of the -air chamber 13 and cause the combustion air to flow radially toward the series of vanes 16 with the major portion of the air contacting the vanes at the rear wall of the air chamber housing 14 where tihe series of vanes lhave their smallest diameters. To accomplish this, the air distribution shroud 17 may have a series of openings 18 therein at the end of the shroud adjacent the rear Vwall o-f the housing 14 so that the shroud causes the air to ow around the outside of the air chamber and then pass inwardly through the openings 18 in a substantially radial direction. If desired, these openings 18 in the portion of the air distribution shroud adjacent the air inlet opening 15 tothe air chamber may be smaller than the remainder of the openings in the air distribution shroud to create a greater resistance to the flow of air through the shroud at the point of air supply and cause a more uniform flow of air inwardly toward the vanes. Alternatively, in lieu of the series of openings 18, the air distribution shroud may be designed to terminate a predetermined distance short of the rear wall of `the air chamber housing 14.

The fuel is entrained in the combustion air immediately prior to the air entering the combustion chamber and, according to the present invention, this fuel may be any desired fluid fuel such as a gas, light oils, or heavy Ifuels such as viscous residual oils, tars, and asphalt. The liquid fuels are injected into the path of travel of the :combustion air through a conventional fuel atomizing nozzle 20 which terminates coaxially of the combustion chamber at a position in advance of the forward edges of the vanes 1d. The fuel atomizing nozzle 24)' i may be supported in this desired position, for example, by means of a bracket 21 carried by the rear `wall of the air chamber `housing 14. If a gaseous fuel is to be burned, a conventional gas injecting nozzle Z2 which surrounds the liquid fuel nozzle 2t? may be used to inject the gaseous fuel into the air stream. With this, a combination of gaseous and liquid `fuel may be burned simultaneously if desired. Preferably, the fuel is injected into the stream of combustion air at such a point so that a conical fuel spray delivered by the fuel injector enters the combustion chamber without actually impinging upon the edge of the inlet yopening 12 to the combustion chamber, and the cone angle of the spray cone preferably should be such that the spray cone, when extended *beyond the opening 12, would intersect the side wall lof the combustion chamber.

With this above described structure, the combustion air forced through the air distribution chamber, is `distributed equally about the periphery of the chamber and then ows radially inward through the distribution shroud toward the series of vanes 16. Thereafter, the air passes through the vanes wherein a swirling movement is imparted to the air and the air is forced forwardly into the combustion chamber 1t)- through the central `opening 12 in the form of a swirling annulus which will diverge outwardly as it enters the combustion chamber. if desired, the rear portion of the opening 12 may be tapered inwardly as indicated at 19 from a diameter equal to the distance between the inner edges of opposite vanes at a point adjacent the rear of the back wal-l of the combustion chamber to a diameter equal to the desired diameter of the opening 12 in order to decrease resistance to the flow of the combustion air. As illustrated in the drawings, the fuel injector terminates adjacent the inlet end of the inlet opening 12 to the combustion chamber thereby `leaving a Void centrally of the path of travel lof the swirling combustion air which will initiate the formation of a vortex along the center line of the combustion chamber. This vortex, along with similar vortices formed within the combustion chamber peripherally of the inlet opening 12 create the desired turbulence and path Iof travel of the fuel-air mixture within the combustion chamber and cause the fuel-air mixture to be maintained within the combustion chamber a sufcient length of time to permit combustion of the fuel to `be substantially completed within the combustion chamber.

From the foregoing, it will be apparent that the present invention provides a burner having novel air inlet and control means to cause the combustion air to follow a predetermined path into and through the combustion chamber with a minimum resistance to the flow of the air. In practice, it has been found that as low as l2 to l inches of water is a suicient pressure for the air supply for a burner `operating at full load and burning fuel at a rate which may be greatly in excess of l million B.t.u.s per hour per cubic foot of combustion space. rIhis is to be compared with other burners of this type wherein a pressure `of approximately 20 inches of Water or higher is required to obtain the desired flow of combustion air. This decrease in required pressure for the `combustion air results in a considerable saving in the cost of auxiliary equipment used in conjunction with this burner. Also, it has ybeen found in practice that this particular air inlet and air ow control means permits a more rapid rate of burning of the fuel than is possible in prior burners of this type. Furthermore, it will be apparent that the present invention provides a novel burner which is of relatively simplified construction and may be manufactured easily and cheaply.

While particular embodiments of the present invention have been illustrated and described herein it is not intended to limit the invention to such a disclosure and changes and modifications may be incorporated and embodied therein within the scope of the following claims.

I claim:

l. ln a combustion device for fluid fuel comprising a substantially tubiform combustion chamber having rear and side walls and being open at the front, means defining an inlet opening to said combustion chamber substantially at the mid point of said chamber rear wall extending through the rear wall thereof, a combustion air supply housing mounted outwardly adjacent the rear wall of said combustion chamber dening an enclosed air chamber, said housing including a front wall positioned in engagement with the rear surface of the rear wall of said combustion chamber, a rear wall spaced from said housing front wall and a peripheral side wall, means defining a central opening in said housing front wall coaxial with the inlet opening in said combustion chamber and of a diameter at least equal to the diameter of said inlet opening at a point adjacent -t-he rear surface of the rear wall of said combustion chamber, means to supply combustion air to the interior of said air chamber adjacent the peripheral side wall thereof and cause the combustion air to flow through said combustion chamber iniet opening into said combustion chamber', a generally cylindrical tube -of substantially uniform diameter smaller than the diameter of said combustion chamber inlet opening coaxial with said combustion chamber inlet opening and extending through the rear Wall of said housing and terminating at said inlet opening adjacent the front wall of said housing, means to supply fuel to said combustion chamber through said cY- lindrical tube, a series of air directing vanes extending from the rear wall of said housing to the front wall of said housing and disposed concentrically about the axis of said combustion chamber inlet opening, said vanes being spaced from each `other providing openings therebetween and positioned to impart a swirling movement to the combustion air entering the combustion chamber through said inlet opening, the vanes extending from the rear wall of said housing at a point adjacent said cylindrical tube and diverging substantially uniformly outward away from each other and the axis of said inlet opening in a direction toward said combustion chamber and terminating at the front wall of said housing adjacent the peripheral edge of said central opening with the innermost edges of the vanes at the front wall of said housing lying in an imaginary circle of a diameter equal to the diameter of said combustion chamber inlet opening at the rear surface of the rear wall of said combustion chamber and bai-lie means positioned intermediate said vanes and the peripheral side wall of said air chamber surrounding said vanes, said bathe means being operable to distribute the air uniformly about the ends of the vanes adjacent the rear wall of said air chamber.

2. In a combustion device for iluid `fuel comprising a substantially tubiform combustion chamber having rear and side walls and being open at the front, means defining an inlet opening to said combustion chamber substantially at the midpoint of said chamber rear wall extending through the rear wall thereof, a combustion air supply housing mounted outwardly adjacent the rear wall of said combustion chamber defining an enclosed air chamber, said housing including a front wall positioned in engagement with the rear surface of the -rear wall of said combustion chamber, a rear wall spaced from said housing front wall and a peripheral side wall, means defining a central opening in said housing front Wall coaxial with the inlet opening in said combustion chamber and of a diameter at least equal to the `diameter of said inlet opening at a point adjacent the rear surface of the rear wall of said combustion chamber, means to supply combustion air to the interior of said air chamber adjacent the peripheral side wall thereof and cause the combustion air to flow through said combustion chamber inlet opening into said combustion chamber, a generally cylindrical tube of substantially uniform diameter smaller than the diameter of said combustion chamher inlet opening coaxial lwith said combustion chamber inlet opening and extending through the rear Wall 0f said housing and terminating at said inlet opening aidjacent the front Wall of said housing, means to supply fuel to said combustion chamber through said cylindrical tube, a series of air directing vanes extending from the rear Wall of said housing to the front wall of Said housing and disposed concentrically about the axis of said combustion chamber inlet opening, said vanes being spaced from each other providing openings therebetween and positioned to impart a swirling movement to the combustion air entering the combustion chamber through said inlet opening, the Vanes extending from the rear Wall of said housing at a point adjacent said cylindrical tube and diverging substantially uniformly outward away from each other and the axis of said nlet opening in a direction toward said combustion cham- `ber and terminating at the front wall of said housing adjacent the peripheral edge of said central opening, and

balile means positioned intermediate said vanes and the peripheral side Wall of said air chamber surrounding said vanes, said bafie means being operable to distribute the air uniformly albout the ends of the vanes adjacent the rear wall of said air chamber.

3. Apparatus in accordance with claim 2 wherein said bate means comprises an annular plate positioned adjacent the rear Wall of the combustion chamber surround. ing said vanes.

References Cited in the le of this patent UNITED STATES PATENTS 1,374,683 Reid Apr. 12, 1921 1,950,980 Frisch Mar. 13, 1934 2,087,869 Blodgett .Tuly 20, 1937 2,806,517 Te Nuyl Sept. 17, 1957 FOREIGN PATENTS 205,892 Great Britain Oct. 26, 1923 

